1. Field of the Invention
The present invention relates to a light source apparatus suitable for an endoscope and an endoscope apparatus.
2. Description of the Related Art
Conventionally, endoscopes are widely used which are designed to observe a region to be examined and conduct various treatments by inserting an elongated endoscope into a body cavity or the like. For such endoscopes, light source apparatuses are used to perform intracavitary photographing. In recent years, light source apparatuses may also have been used which adopt a semiconductor light source such as an LED as a light emitting section. Such light source apparatuses can perform light adjustment control of an LED through PWM control that changes a duty ratio of drive pulses or current control that changes an LED current.
The light source apparatuses using such LED light sources generate heat according to the amount of light emission and the light quantity fluctuates due to a temperature variation during heat generation. Thus, Japanese Patent Application Laid-Open Publication No. 2007-149469 (hereinafter referred to as “Document 1”) discloses an apparatus that cools an LED using a Peltier element. The apparatus according to Document 1 drives a Peltier element using a periodic pulse current that rises earlier than the rise of a pulse current of a drive current of the LED and thereby enables cooling to be performed following heat generation of the pulsating LED.